Collapsible tube



FIG. 1 is a front perspective view of a collapsible tube in accordance with my new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a left side elevational view thereof, a right side elevational view being identical;

FIG. 4 is a top plan view thereof;

FIG. 5 is a bottom plan view thereof; and,

FIG. 6 is a rear perspective view thereof. 

The ornamental design for a collapsible tube, as shown and described. 